1. Field of the Invention
The present invention relates to electronic circuits, and more specifically to a voltage regulation device for supplying a regulated voltage to integrated circuits in radio-frequency applications.
2. Description of Related Art
In some radio-frequency (RF) applications, an integrated circuit is powered from the RF wave that is transmitted to it. An example of an application of this type is the "contactless smart card". In this particular application, the card is powered from the RF wave transmitted by a card reader. The microcircuit (i.e., the integrated circuit chip or chips contained in the card) includes particular RF transmission/reception means for communications with a reader, and processing means for processing data such as that contained in the microcircuit memory. These various means must be supplied with a regulated voltage.
The voltage supplied to the internal circuitry must have a certain level that is as stable as possible. This is conventionally obtained by means of a shunt circuit that enables the discharging of the output node if necessary, so as to maintain the level at the output. With such a circuit, the load on the extraction device is permanent. This has an impact on the operable distance of communication between the card and the reader. The greater the power that must be extracted from the RF wave, the smaller the allowable distance between the card and the reader.